self.onmessage = function (e) {
const timer = setInterval(() => {
let now = Date.now(),
end = e.data.end,
leftTime = end - now;
if (leftTime > 0) {
self.postMessage({
leftTime
});
} else {
clearInterval(timer);
self.postMessage({
leftTime: 0
});
self.close();
}
}, 60)
}